Formation of a Buffer Layer for Graphene on C-Face SiC{0001}

• Published in: Journal of electronic materials 2014-04, Vol.43 (4), p.819-827
• Main Authors: He, Guowei, Srivastava, N., Feenstra, R. M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Corrosion; Corrosion mechanisms; Cross-disciplinary physics: materials science; rheology; Electron diffraction and scattering; Electronics; Electronics and Microelectronics; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Heat conductivity; Instrumentation; Low-energy electron diffraction (leed) and reflection high-energy electron diffraction (rheed); Materials Science; Metals. Metallurgy; Optical and Electronic Materials; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Solid State Physics; Specific materials; Structure of solids and liquids; crystallography
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-013-2901-8

Graphene films prepared by heating the SiC ( 000 1 ¯ ) surface (the C-face of the {0001} surface) in a Si-rich environment have been studied using low-energy electron diffraction (LEED) and low-energy electron microscopy. Upon graphitization, an interface with 43 × 43 - R ± 7 . 6 ∘ symmetry is observed by in situ LEED. After oxidation, the interface displays 3 × 3 - R 30 ∘ symmetry. Electron reflectivity measurements indicate that these interface structures arise from a graphene-like “buffer layer” that forms between the graphene and the SiC, similar to that observed on Si-face SiC. From a dynamical LEED structure calculation for the oxidized C-face surface, it is found to consist of a graphene layer sitting on top of a silicate (Si 2 O 3 ) layer, with the silicate layer having the well-known structure as previously studied on bare SiC ( 000 1 ¯ ) surfaces. Based on this result, the structure of the interface prior to oxidation is discussed.